- All Implemented Interfaces:
Serializable
public class SealedObject extends Object implements Serializable
Given any Serializable object, one can create a SealedObject that encapsulates the original object, in serialized format (i.e., a "deep copy"), and seals (encrypts) its serialized contents, using a cryptographic algorithm such as AES, to protect its confidentiality. The encrypted content can later be decrypted (with the corresponding algorithm using the correct decryption key) and de-serialized, yielding the original object.
Note that the Cipher object must be fully initialized with the correct algorithm, key, padding scheme, etc., before being applied to a SealedObject.
The original object that was sealed can be recovered in two different ways:
- by using the
getObject
method that takes aCipher
object.This method requires a fully initialized
Cipher
object, initialized with the exact same algorithm, key, padding scheme, etc., that were used to seal the object.This approach has the advantage that the party who unseals the sealed object does not require knowledge of the decryption key. For example, after one party has initialized the cipher object with the required decryption key, it could hand over the cipher object to another party who then unseals the sealed object.
- by using one of the
getObject
methods that take aKey
object.In this approach, the
getObject
method creates a cipher object for the appropriate decryption algorithm and initializes it with the given decryption key and the algorithm parameters (if any) that were stored in the sealed object.This approach has the advantage that the party who unseals the object does not need to keep track of the parameters (e.g., an IV) that were used to seal the object.
- Since:
- 1.4
- See Also:
Cipher
, Serialized Form
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Field Summary
Modifier and TypeFieldDescriptionprotected byte[]
The cryptographic parameters used by the sealing Cipher, encoded in the default format. -
Constructor Summary
ModifierConstructorDescriptionSealedObject(Serializable object, Cipher c)
Constructs a SealedObject from any Serializable object.protected
SealedObject(SealedObject so)
Constructs a SealedObject object from the passed-in SealedObject. -
Method Summary
Modifier and TypeMethodDescriptionReturns the algorithm that was used to seal this object.Retrieves the original (encapsulated) object.Retrieves the original (encapsulated) object.Retrieves the original (encapsulated) object.
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Field Details
-
encodedParams
protected byte[] encodedParamsThe cryptographic parameters used by the sealing Cipher, encoded in the default format.That is,
cipher.getParameters().getEncoded()
.
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Constructor Details
-
SealedObject
Constructs a SealedObject from any Serializable object.The given object is serialized, and its serialized contents are encrypted using the given Cipher, which must be fully initialized.
Any algorithm parameters that may be used in the encryption operation are stored inside of the new
SealedObject
.- Parameters:
object
- the object to be sealed; can be null.c
- the cipher used to seal the object.- Throws:
NullPointerException
- if the given cipher is null.IOException
- if an error occurs during serializationIllegalBlockSizeException
- if the given cipher is a block cipher, no padding has been requested, and the total input length (i.e., the length of the serialized object contents) is not a multiple of the cipher's block size
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SealedObject
Constructs a SealedObject object from the passed-in SealedObject.- Parameters:
so
- a SealedObject object- Throws:
NullPointerException
- if the given sealed object is null.
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Method Details
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getAlgorithm
Returns the algorithm that was used to seal this object.- Returns:
- the algorithm that was used to seal this object.
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getObject
public final Object getObject(Key key) throws IOException, ClassNotFoundException, NoSuchAlgorithmException, InvalidKeyExceptionRetrieves the original (encapsulated) object.This method creates a cipher for the algorithm that had been used in the sealing operation. If the default provider package provides an implementation of that algorithm, an instance of Cipher containing that implementation is used. If the algorithm is not available in the default package, other packages are searched. The Cipher object is initialized for decryption, using the given
key
and the parameters (if any) that had been used in the sealing operation.The encapsulated object is unsealed and de-serialized, before it is returned.
- Parameters:
key
- the key used to unseal the object.- Returns:
- the original object.
- Throws:
IOException
- if an error occurs during de-serialiazation.ClassNotFoundException
- if an error occurs during de-serialiazation.NoSuchAlgorithmException
- if the algorithm to unseal the object is not available.InvalidKeyException
- if the given key cannot be used to unseal the object (e.g., it has the wrong algorithm).NullPointerException
- ifkey
is null.
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getObject
public final Object getObject(Cipher c) throws IOException, ClassNotFoundException, IllegalBlockSizeException, BadPaddingExceptionRetrieves the original (encapsulated) object.The encapsulated object is unsealed (using the given Cipher, assuming that the Cipher is already properly initialized) and de-serialized, before it is returned.
- Parameters:
c
- the cipher used to unseal the object- Returns:
- the original object.
- Throws:
NullPointerException
- if the given cipher is null.IOException
- if an error occurs during de-serialiazationClassNotFoundException
- if an error occurs during de-serialiazationIllegalBlockSizeException
- if the given cipher is a block cipher, no padding has been requested, and the total input length is not a multiple of the cipher's block sizeBadPaddingException
- if the given cipher has been initialized for decryption, and padding has been specified, but the input data does not have proper expected padding bytes
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getObject
public final Object getObject(Key key, String provider) throws IOException, ClassNotFoundException, NoSuchAlgorithmException, NoSuchProviderException, InvalidKeyExceptionRetrieves the original (encapsulated) object.This method creates a cipher for the algorithm that had been used in the sealing operation, using an implementation of that algorithm from the given
provider
. The Cipher object is initialized for decryption, using the givenkey
and the parameters (if any) that had been used in the sealing operation.The encapsulated object is unsealed and de-serialized, before it is returned.
- Parameters:
key
- the key used to unseal the object.provider
- the name of the provider of the algorithm to unseal the object.- Returns:
- the original object.
- Throws:
IllegalArgumentException
- if the given provider is null or empty.IOException
- if an error occurs during de-serialiazation.ClassNotFoundException
- if an error occurs during de-serialiazation.NoSuchAlgorithmException
- if the algorithm to unseal the object is not available.NoSuchProviderException
- if the given provider is not configured.InvalidKeyException
- if the given key cannot be used to unseal the object (e.g., it has the wrong algorithm).NullPointerException
- ifkey
is null.
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